Liquid recycling system

ABSTRACT

An apparatus and method is disclosed for recycling contaminated industrial liquids. In the preferred embodiment, a conventional, medium-sized &#34;van&#34; type of truck houses, transports and powers a dual-loop assembly. A filter-loop assembly receives and stores recycling liquid in a waste liquid holding tank. The liquid is pumped through a pasteurizing heater and a separating centrifuge and back to the tank. Filter-test valves in the filter-loop enable testing to determine desired heating and separation. 
     When flow-rate adjustments produce satisfactory heating and separation, the recycling liquid is directed through a cooler, out of the filter-loop and into an additive-loop assembly where the liquid is pumped from a clean liquid holding tank, by additive compound injections, and back to the clean tank. Additive-test valves in the additive-loop enable testing to determine required quantities of specific additive compounds. When tests indicate satisfactory levels of the compounds, the recycling liquid is directed out of the additive-loop assembly and out of the system. The filter and additive test valves enable periodic testing during recycling to insure consistency. If the recycling becomes inadequate, the filter-loop and/or additive-loop is closed until changes in the flow-rate or additive injection rates again produce satisfactory recycling.

RELATED APPLICATION

This application is a continuation of application Ser. No. 07/482,342,filed Feb. 20, 1990, now U.S. Pat. No. 5,026,488, issued Jun. 25, 1991.

BACKGROUND OF THE INVENTION

The present invention relates to mechanical devices and methods forrecycling contaminated liquids.

Demand for recycling of contaminated industrial liquids has increaseddramatically in recent years as a result of growing concern over thedeleterious environmental impact of unregulated disposal of suchliquids. The current costs of proper disposal of certain industrialliquids, such as metalworking coolants and lubricants, frequently exceedtheir purchase costs. Consequently, maximizing the useful life of suchliquids, through recycling, offers significant economic andenvironmental benefits.

Metalworking coolants and lubricants are but a typical example of a vastarray of industrial liquids that pose potential environmental hazardsand are amenable to recycling. Other examples include hydraulic fluidfor operating hydraulic motors and vehicle lifts, used motor oil,antifreeze and many petroleum-based liquids contaminated withwater-based liquids, and vice versa.

Some progress has been made in providing recycling devices for specificneeds. Large users of certain liquids have installed on-site recyclingsystems that utilize fine screens to separate particulate contaminants,and centrifuges to separate components of immiscible liquids. Largemanufacturers may employ a recycling processing system that moves withina plant to different metalworking machines to filter the machine toolcoolant, as shown in U.S. Pat. No. 4,772,402 to Love. Smallermanufacturers could utilize a trailer or truck borne device, on aperiodic basis, that screens, pasteurizes and then centrifugesmetalworking coolants, as shown in U.S. Pat. No. 4,636,317 to Lewis.

Unfortunately, none of these alternatives have gained widespreadacceptance. The principal impediments to the commercial viability ofsuch recycling devices are, first, the extraordinary variety ofenvironmentally hazardous industrial liquids and, second, the diversenature of the users of such liquids. From General Motors Corporation tocorner automobile service stations and small metalworking "job shops",industrial coolants, lubricants and related liquids are employed in hugequantities under varying conditions.

Some liquids are employed at a specific temperature range thatencourages rapid bacterial growth, producing corrosive metabolites andrelated by-products. Another user may employ the exact same liquid at adifferent temperature such that the resulting contamination problem isprimarily from particulate matter or possibly contamination with aninsoluble liquid. A particular user may exhaust a substantial quantityof a first specific liquid while only a smaller quantity of a secondhazardous liquid is depleted during the same period of time. Acquisitionof an on-site recycling system may not include recycling of both liquidsdue to the differing characteristics of the liquids. Known mobilerecycling devices may not economically recycle both liquids. Therefore,such a user could tend to invest in premature, off-site disposal only,because some off-site disposal would always be necessary.

Additionally, most contaminated industrial liquids are stored in amanner that complicates recycling. Storage containers of the liquidstypically produce stratified layers. A top layer may consist of foamwith fine particulate matter ("fines") adhering to bubbles. Anintermediate layer below the foam may include the lighter of twoinsoluble liquids, such as a petroleum-based liquid. The bulk of theliquid may be another lower layer of a heavier insoluble liquid, with afinal bottom layer of settled fines and precipitated by-products ofmicrobial activity.

Known systems for recycling such contaminated liquids are designed tooperate on liquids having specific characteristics. The systems cannotbe readily altered to adapt to different liquids or the stratifiedlayers found in specific, contaminated, stored liquids. The systems aredesigned to set an intake side of the recycling system to a specificflow-rate appropriate to produce specific temperature ranges andcentrifugation effects. Once the intake flow-rate is set, the systemsoperate on a straight-run mode affording no mid-run testing and changeto satisfy requirements of changing characteristics of the liquid as astorage container is depleted, or when the intake moves from one storagecontainer (e.g., a fifty-five gallon barrel) to another.

Another reason known recycling systems have not attained wide-spreadcommercial success is that certain industrial liquids contain a varietyof chemical additives in relatively small quantities. These additivesare very important in determining the effectiveness of the liquids. Theyinclude biocides (bacterial growth suppressing agents), pH buffers,emulsifying agents, anti-foam chemicals, deodorizers, concentratedliquid boosters, among others. The depletion or deterioration of suchagents varies with the nature of use and conditions of storage of theliquids. Current recycling systems are unable to monitor the additiverequirements of filtered liquids during recycling. Post recyclingtesting to determine additive requirements is a lengthy, costly andineffective procedure.

Still another problem with existing recycling systems is the substantialenergy requirement to economically operate the systems. The energyrequired to heat typical contaminated liquids to an effectivepasteurizing temperature, at a flow-rate that is commercially viable,requires known mobile trailer or truck borne systems to utilizeelectrical energy provided at the storage site of the contaminatedliquid. Although this is possible at some large facilities, such arequirement presents significant logistical problems in mostcircumstances. Additionally, the billing complications arising from suchan energy-use arrangement deters periodic utilization of a mobilerecycling system-contractor.

Consequently, because of structural limitations, known liquid recyclingsystems are unable to effectively recycle the wide variety of hazardousindustrial liquids or service the periodic recycling needs of mosthazardous liquid users.

Accordingly, it is the general object of the present invention toprovide an improved liquid recycling system that overcomes the problemsof the prior art.

It is another general object to provide an improved liquid recyclingsystem that offers an inexpensive alternative to costly prematuredisposal of hazardous industrial liquids.

It is a more specific object to provide a liquid recycling system thatcan readily change its filtering capacities to efficiently service avariety of different hazardous industrial liquids.

It is another object to provide a liquid recycling system that canreadily change its filtering capacities, while recycling a hazardousindustrial liquid.

It is another object to provide a liquid recycling system that affordsmonitoring of chemical additive requirements of the liquid beingrecycled, and provides for metering of such additives into the liquid,during recycling.

It is yet another object to provide a liquid recycling system that ismobile and self-powered.

The above and other objects and advantages of this invention will becomemore readily apparent when the following description is read inconjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

An improved liquid recycling system is disclosed for recycling hazardousindustrial liquids. The system includes mechanical components that arehoused within, and transported by, a conventional, medium-sized,enclosed "van" type of truck. All the components are powered by theengine of the van.

In the preferred embodiment, the invention comprises a sequential,dual-loop assembly affixed to a contaminated liquid intake head; amaster control panel and test station integrated with the loops; and, arecycled-liquid discharge nozzle. A first, or filter-loop assemblyreceives contaminated liquid that has passed through fine screenfilters. The liquid is pumped from a waste liquid holding tank, througha pasteurizing heater, to kill bacteria and lower the liquid'sviscosity, and a centrifuge, to further separate fine particles andundesirable insoluble liquids. Then the liquid is pumped back to thewaste liquid holding tank, and cooled, completing the filter-loop.

The master control panel monitors and controls the temperature of theliquid in the filter-loop by measuring the pre-heating and post-coolingtemperature and allowing an operator to regulate flow-rates through theheater and cooler to increase or decrease the temperature. The controlpanel includes a test station which provides for post-centrifugeextraction of a sample of the liquid to test the quality of separationproduced by the centrifuge. The operator can adjust the flow-rate intothe centrifuge to adjust the separation produced by it to the desiredrate. Flow-rate through the centrifuge and resulting separation qualitycan also be regulated by altering the viscosity of the liquid throughpre-centrifuge control of the temperature of the liquid. The operatorrepeats the testing of the liquid within the filter-loop until thedesired flow-rate, post-cooling temperature and liquid quality areattained. The liquid is then directed into a clean liquid holding tank.

Then the liquid is pumped through a second, or additive-loop assembly.The liquid flows from the clean liquid holding tank to a second liquidextraction test valve on the control panel where a sample is extractedfor testing. The test determines the quantity of needed additives.Additive-flow control metering valves on the control panel are adjustedto inject into the liquid the required additives at the rates determinedby the test. The liquid is then pumped back into the clean liquidholding tank, and circles through the additive-loop, until test liquidsatisfies the target requirements for the particular liquid beingrecycled. When the requirements are met, the liquid is discharged torecycled liquid storage tanks.

In use, an operator first takes a core sample of the liquid to berecycled. A transparent tube extracts the core sample of the liquid asit is stored. From the tube, the operator can visually determine theextent of stratification of the stored liquid and anticipate thesequence of adjustments, if any, that will be needed to compensate forthe stratification. For example, if water-based metalworking liquids arebeing recycled, typically a layer of oil-based contaminants will occupya top region of the storage container and the layer will have adistinctive color that is different than the color of the lower,water-based liquid.

A vacuum hose for the liquid recycling system is also transparent and anintake head is placed well below the oil-based, liquid layer so that thewater-based liquid is withdrawn first. When the operator observes thedistinctive color of the oil-based layer in the intake line, adjustmentsare made to insure its proper recycling. If necessary, further intake isstopped until the liquid already on-board is completely recycled, andthen the distinctive colored liquid enters the system and is thoroughlytested within the filter and additive loops prior to discharge.

As the recycling system is operated, the operator administers regularperiodic tests of liquid in the filter and additive loops. If anycorrections are needed, the operator can make them during the recycling.The loop needing correction may be closed, stopping discharge out of theloop, until the flow-rate or the injection rate of additives is adjustedto again produce satisfactory liquid.

Most pumps and the centrifuge are operated by electrically actuated,mechanical, power takeoffs from the engine of the van. Remaining pumpsare operated by electrical energy provided by the van's engine. Coolantfrom the engine of the van provides heat, raising the temperature of therecycled liquid, while coolant from the air conditioner of the van isused to cool the liquid back down, to inhibit post-filtration bacterialgrowth and afford immediate utilization of the recycled liquid.Consequently, a wide variety of hazardous industrial liquids indiffering conditions of storage can be recycled by this mobile,self-powered, liquid recycling system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of a liquid recycling systemconstructed in accordance with the present invention wherein the systemis housed within, powered and transported by a conventional "van" typeof truck, with a side and roof of the van partially cutaway to show thesystem during operation;

FIG. 2 is a fragmentary top plan view of the liquid recycling system ofFIG. 1, with the roof of the van cutaway to show a floor plan of thesystem;

FIG. 3 is a block diagram of the liquid recycling system of the presentinvention;

FIG. 4 is a block diagram of a vacuum mechanism of the recycling system;

FIG. 5 is a block diagram of a filter-loop assembly used in therecycling system;

FIG. 6 is a block diagram of an additive-loop assembly used in therecycling system;

FIG. 7 is a block diagram of a clean-water wash cycle used in therecycling system; and

FIG. 8 is a plan view of a master control panel and test station of therecycling system.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in detail, the preferred embodiment of aliquid recycling system is shown and generally designated by the number10. FIGS. 1-3 show overall views of the invention and FIGS. 4-8 showportions thereof. The invention basically comprises a filter-loop 12(FIG. 5) integrally associated with an additive-loop 14 (FIG. 6), bothof which are monitored and controlled through a master control panel 16(FIG. 8) to filter and add depleted and/or rejuvenating compounds tohazardous industrial liquids, thereby recycling them.

As best shown in FIG. 5, in the filter-loop 12, liquid to be recycled(hereafter "recycling liquid") is stored in waste liquid holding tank 18and then pumped through a pre-heater/cooler 20, and a heater 22 topasteurize the liquid and change its viscosity. Then the recyclingliquid passes through a centrifuge or mechanical separator 24 toseparate out fine particles and insoluble unwanted liquids. The liquidis then pumped back to the waste liquid holding tank 18. An operator 26controls the temperature and flow-rate of the liquid, via the mastercontrol panel 16, thereby effecting the quality of the liquid exitingthe centrifuge 24. When the quality is satisfactory, the operatordirects the recycling liquid to a cooler 28 instead of the waste holdingtank 18. The cooler reduces the temperature of the recycling liquid sothat it can be used immediately. The lower temperature also inhibitsbacterial growth. From the cooler 28, the liquid flows to a clean liquidholding tank 30, completing the filter-loop 12.

As seen in FIG. 6, in the additive-loop 14, recycling liquid is pumpedfrom the clean liquid holding tank 30 through the control panel 16 wherea plurality of chemical additives can be selectively metered into theliquid through an additive manifold 32. The liquid flows back to theclean liquid holding tank 30 until tests by the operator 26 at thecontrol panel 16 indicate the recycling liquid meets or exceeds targetspecifications. Then, the liquid is directed out of the additive-loop 14and out of the liquid recycling system 10 through a discharge nozzle 34.The liquid recycling system 10 is housed within, transported and poweredby a conventional "van" 36 type of truck.

As best shown in FIG. 7, the liquid recycling system 10 includes avacuum mechanism 38 that allows recycling liquid to be taken into theliquid recycling system 10 with no contact between the liquid and avacuum blower or pump 40 that creates suction to take in the liquid.Known vacuum blowers are effective for this purpose such as vacuumblower Model No. 65109020, manufactured by Roots/Dresser, Inc. ofPittsburgh, Pa.

A suction side 41 of vacuum blower 40 is in fluid connection with mainvacuum line 42 which leads and, in operation, applies suction to wasteliquid holding tank 18 through suction inlet 43. Interconnecting vacuumline 44 interconnects the waste holding tank 18 and a waste disposaltank 46. An open end 47 of interconnecting vacuum line 44 is adjacentto, and, in operation, applies suction to, a bottom area (not shown) ofwaste disposal tank 46. Affixed to, and in fluid connection with, thewaste disposal tank 46 is a vacuum intake line 48. Vacuum intakesolenoid valve 50 opens up and shuts off flow through vacuum intake line48 and is actuated by vacuum intake solenoid switch 52 located on themaster control panel 16, and in electrical connection with valve 50.Vacuum hose 54 is in fluid connection with vacuum intake line 48 and ismounted on vacuum reel 56. The vacuum hose 54 is made of knowntransparent plastic materials and has an intake head 58 mounted upon anend of the hose 54 that rolls off of the reel to extend and descend intoa storage container (not shown) for liquid to be recycled.

Vacuum mechanism 38 includes a fine filter screen trap box 60 betweenintake head 58 and vacuum reel 56, in fluid connection with vacuum hose54. The trap box 60 has a first disposable fine filter screen bag 62through which all recycling liquid must flow. A second disposable finefilter screen bag 64 is located below, and in fluid connection with, asecond recycling liquid inlet 66 in waste disposal tank 46. A thirddisposable fine filter screen bag 68 is located below, and in fluidconnection with, a third recycling liquid inlet 70 in waste holding tank18. First, second and third disposable fine filter screen bags 62, 64,68 are constructed of known filter material of varying pore sizes, suchas nylon.

Also included in vacuum mechanism 38 is a float switch 72 affixed to atop-side 74 of waste holding tank 18. The float switch 72 is inelectrical connection with vacuum blower 40 so that the blower isswitched off when the amount of recycling liquid in the waste holdingtank 18 exceeds a pre-set level on the switch 72. A vacuum-breaker valve76 is also affixed to the top-side 74 of the waste holding tank 18. Thevalve 76 opens to let air into tank 18 when the pressure within the tankdrops below a pre-set level.

As seen in FIG. 4, an exhaust side 78 of vacuum blower 40 is in fluidconnection with blower exhaust line 80, which leads to, and is affixedto, exhaust pipe 82. Also shown in FIG. 7, an accumulated-waste suctionline 84 is affixed to a waste line inlet 85 in waste disposal tank 46. Awaste line solenoid valve 86 intersects accumulated-waste suction line84 and is electrically actuated by waste line switch 88 on the controlpanel 16. Test liquid drain suction line 90 is in fluid connection with,and affixed to, the accumulated-waste suction line 84, adjacent to thewaste line solenoid valve 86, and connects accumulated-waste suctionline 84 to a test liquid disposal tray 91 at the master control panel16. Centrifuge wash suction line 92 is in fluid connection with andaffixed to the accumulated-waste suction line 84, adjacent the wasteline solenoid valve 86, and connects accumulated waste suction line 84to a centrifuge wash product storage container 94.

As shown in FIG. 2, vacuum blower 40 is powered by a power takeoff shaft96. The power takeoff shaft 96 is designed and manufactured by theinventor herein. Essentially, it utilizes a conventional belt-drivepulley mechanism (not shown) with belts interconnecting a pulley on thecrank shaft of the van's 38 engine (not shown) and a standard electricclutch on the shaft 96. The shaft spins a first conventional belt drivemechanism 98 and blower electric clutch 100. A blower electric clutchswitch 102 located on the control panel 16 actuates the blower 40 byengaging the blower electric clutch 100 while the shaft 96 is spinning.

In operation, the vacuum mechanism 38 applies suction, when the blower40 is turned on, through the main vacuum line 42, the waste liquidholding tank 18, the waste disposal tank 46, the vacuum intake line 48,the vacuum hose 54, and the intake head 58. When the operator 26 insertsthe intake head 58 into a container of liquid to be recycled, the liquidresponds to the suction and flows through the intake head 58, vacuumhose 54, intake line 48, waste disposal tank 46 and into the wasteliquid holding tank 18. In so traveling, the recycling liquid passesthrough the first, second and third disposable fine filter bags, 62, 64,68 respectively without being exposed to any moving parts or any pumpcomponents.

After recycling is completed, the operator can close vacuum intakesolenoid valve 50 from its switch 52 and open waste line solenoid valve86 from its switch 88, while the vacuum blower 40 is applying suction towaste disposal tank 46. That allows any recycling liquid discarded tothe test liquid disposal tray 91 to be sucked into disposal tank 46, aswell as any waste products washed from the centrifuge 24 and stored inthe centrifuge wash product storage container 94. The discarded testrecycling liquid and centrifuge waste products can then be removed fromthe waste disposal tank 46 through the waste disposal valve 104 whenappropriate.

As best shown in FIGS. 2 and 5, in the filter-loop 12 portion of theliquid recycling system 10, recycling liquid is pumped by, viaconventional piping (not shown), and passes through, a filter-loop pump106. Pump 106 is a commercially available pump, such as pump modelnumber 560 manufactured by Cat Pumps, Inc. of Minneapolis, Minn. As seenin FIG. 2, pump 106 is powered by power takeoff shaft 96, which spins asecond conventional belt drive mechanism 108 and filter-loop pumpelectric clutch 110. A filter pump electric clutch switch 112, locatedin the control panel 16, actuates the filter-loop pump 106 by engagingits electric clutch 110 while shaft 96 is spinning.

Certain types of recycling liquid tend to produce foam. The filter-loop12 includes a de-foaming compound container 114. A standard, knownde-foaming compound, such as "De Foamer", manufactured by Eviron-Lub,Inc., of Indian Orchard, Mass., stored in container 114, flows, viaconventional piping (not shown), from container 114, to a de-foamermetering valve 116 in control panel 16 and then to a de-foamer "T"-joint118 adjacent to a suction side 120 of filter-loop pump 106. Direct flowof the recycling liquid straight through the "T"-valve 118 providessufficient suction upon the de-foaming compound, flowing perpendicularto the recycling liquid, to draw the de-foaming compound into theflowing recycling liquid at a rate determined by the de-foamer meteringvalve 116.

Recycling liquid exits an exhaust side 122 of filter-loop pump 106 andflows, via conventional piping (not shown), to a filter-loop pressuregauge 124; filter-loop flow-rate control valve 126; and recycling abortvalve 127, all of which are located in the control panel 16. Therecycling liquid then flows to the pre-heater/cooler 20, which is anenclosed box-like structure, that has directional, flow-control baffles(not shown) and coiled piping or tubing 128 within. The recycling liquidflows through the tubing 120 absorbing heat, out of pre-heater/cooler 20and into the heater 22. The heater is very similar in structure to thepre-heater/cooler 20, including coiled tubing 130, through which therecycling liquid flows absorbing even more heat from a heat-transfermedium, and directional, flow-control baffles (not shown) within abox-like structure. The heat transfer medium within the heater 22 is anantifreeze-based coolant of the van's 36 engine (not shown). The mediumis directed through conventional, insulated, heater-type hoses (notshown) from the van's engine to the heater 22, and back to the engine.The medium absorbs heat from the engine of the van, which is runningduring operation of the liquid recycling system.

From the heater 22, recycling liquid flows back to the control panel 16to a post-heating temperature gauge 132 and a transparent, glassflow-rate gauge 134. The liquid then flows through a centrifuge"Y"-joint 136 adjacent to solenoid valve panel 138. The "Y"-joint 136splits the recycling liquid flow to either a centrifuge bypass solenoidvalve 140 or a centrifuge entry solenoid valve 142, both of which are onthe solenoid panel 138. Both valves 140, 142 are controlled by acentrifuge flow switch 144 located on the master control panel 16. Theswitch 144 operates such that, if centrifuge entry solenoid valve 142 isopen, then centrifuge bypass solenoid valve 140 must be closed, and viceversa.

Depending upon which of the centrifuge valves 140, 142 is open and whichis closed, the recycling liquid can either by-pass or enter thecentrifuge 24. The centrifuge is a standard "ring-dam" centrifuge forseparating fine suspended particles from a liquid and for separatingimmiscible liquids, such as centrifuge model number 4042230 manufacturedby Alfa-Laval, Inc. of Poughkeepsie, N.Y. As seen in FIG. 2, centrifuge24 is powered by power takeoff shaft 96 that spins a third conventionalbelt drive mechanism 148 and centrifuge electric clutch 150. Acentrifuge electric clutch switch 152, located in the master controlpanel 16, actuates the centrifuge by engaging the centrifuge electricclutch 150 while shaft 96 is spinning.

When the centrifuge 24 is operating, separated, undesirable liquid,flows through separated liquid pipe 154 to a separated liquid storagecontainer 156. Separated particles are stored within the centrifuge 24and washed out of it, after recycling, through separated particle pipe158 to the centrifuge Wash product storage container 94.

Recycling liquid that by-passes the centrifuge, or recycling liquid thatis separated by the centrifuge, flows to a roller pump 160. The rollerpump 160 is a standard, commercially available pump, such as modelnumber 6500 C, manufactured by Hypro, Corp. of New Brighton, Minn. Asseen in FIG. 2, the roller pump is powered by power takeoff shaft 96that spins a fourth conventional belt drive mechanism 162 and rollerpump electric clutch 164. A roller pump electric clutch switch, 166,located in the master control panel 16, actuates the roller pump byengaging the roller pump electric clutch 164 while shaft 96 is spinning.

As seen in FIG. 3, recycling liquid flows from the roller pump 160, viaconventional piping (not shown), to a post-centrifuge "Y"-joint 168,which splits the recycling liquid flow to either a waste liquid holdingtank entry solenoid valve 170 or a cooler entry solenoid valve 172, bothof which valves 170, 172, are on the solenoid valve panel. Both valves170, 172 are controlled by cooler entry switch 174 located on the mastercontrol panel 16. The switch 174 operates such that, if waste liquidholding tank entry solenoid valve 170 is open, then cooler entrysolenoid valve 172 must be closed and vice versa.

If waste liquid holding tank entry solenoid valve 170 is open, recyclingliquid flows back to waste liquid holding tank 18. If cooler entrysolenoid valve 172 is open, recycling liquid flows, as best seen in FIG.5, to pre-heater/cooler 20 where the recycling liquid becomes a heattransfer medium for recycling liquid passing through the coiled tubingof the pre-heater/cooler 20, thereby losing some of its heat. Therecycling liquid flows through the directional-flow baffled interior ofthe pre-heater/cooler 20 and then into the similarly directional-flowbaffled interior of the cooler 28. The cooler includes conventionalcoiled tubing (not shown) through which flows a cooling medium. Thecooling medium is a conventional fluorocarbon compound (e.g., freon)found in air conditioning systems of automobiles and "van" types oftrucks. The fluorocarbon compound is directed through conventionalinsulated hoses from the air conditioning system of the van 38 to coiledtubing (not shown) in the cooler 28, and back to the air conditioningsystem. The flow-rate of the fluorocarbon compound through the cooler 28is controlled by conventional air conditioning valves (not shown) andthereby effects the rate of heat absorption from the recycling liquidpassing through the cooler 28.

Recycling liquid leaves the cooler 28 and flows to a post-coolertemperature gauge 178 and a filter-loop liquid test valve 180, whereoperator 26 can extract some of the recycling liquid for qualitytesting. The recycling liquid then flows to the clean liquid holdingtank 30, and extracted test liquid is held in the test liquid disposaltray 91.

In operation of the filter-loop 12 portion of the recycling system 10,the operator actuates filter-loop pump 106 from the switch 112 for itselectric clutch on the control panel 16, thereby directing recyclingliquid to flow through the filter-loop flow-rate control valve 126 andthrough the pre-heater/cooler 20, heater 22, post heating temperaturegauge 132, transparent flow-rate gauge 134, centrifuge 24, roller pump160, and back to the waste liquid holding tank 18. The centrifuge 24 maybe by-passed by opening centrifuge bypass solenoid valve 140 until thecentrifuge is brought up to operating speed, or during flow-ratealterations to change the temperature of the recycling liquid. Thede-foamer metering valve 116 is adjusted to supply adequate de-foamer tothe recycling liquid.

By observing the recycling liquid passing through the transparentflow-rate gauge 134, the operator can estimate when the recycling liquidhas achieved proper separation. Then cooler diversion switch 174 isopened and the recycling liquid flows through the pre-heater/cooler 20,cooler 28 and is extracted at the filter-loop liquid test valve 180 fortesting. During testing, test valve 180 and cooler diversion switch 174are again closed, keeping the recycling liquid out of the clean liquidholding tank 30. If the test results are unsatisfactory, the operatorcan adjust filter-loop flow-rate control valve 126 until adequateseparation is achieved by the centrifuge 24. In the event adequateseparation cannot be achieved, the operator terminates recycling byopening the recycling abort valve 127 which directs the recycling liquidout of the liquid recycling system, via conventional piping (not shown),through the recycling abort discharge nozzle 181. When recycling isterminated in this manner, centrifuge bypass solenoid valve 140 is open,allowing the recycling liquid to by-pass the centrifuge 24. When testresults are satisfactory, cooler diversion switch 174 is again openedand recycling liquid flows into clean liquid holding tank 30.

As best shown in FIGS. 2 and 6, in the additive-loop 14 portion of therecycling system 10, recycling liquid is pumped by (via conventionalpiping (not shown)), and passes through, an additive-loop pump 182. Pump182 is a commercially available pump, such as model number 560,manufactured by Cat Pumps, Inc. of Minneapolis, Minn. As seen in FIG. 2,pump 182 is powered by the power takeoff shaft 96, which spins a fifthconventional belt drive mechanism 184 and additive-loop pump electricclutch 186. An additive-loop pump electric clutch switch 188, located inthe master control panel 16, actuates the additive-loop pump 182 byengaging its electric clutch 186, while shaft 96 is spinning.

As seen in FIG. 6, recycling liquid then flows from additive-loop pump182 to a first additive-loop pressure gauge 190 and an additive-loopliquid test valve 192, where the operator extracts a test sample of therecycling liquid to evaluate what additives are needed to meet targetspecifications for the recycling liquid. The recycling liquid then flowsfrom the test valve 192, when it is closed, to an additive "Y"-joint 194adjacent the solenoid valve panel 138. The "Y"-joint 194 splits therecycling liquid to a clean liquid holding tank re-entry solenoid valve196 and a discharge solenoid valve 198. Valves 196 and 198 areelectrically controlled by discharge switch 200 located on the controlpanel 16, such that when discharge solenoid valve 198 is open, cleanliquid holding tank re-entry solenoid valve 196 has to be closed, andvice versa.

When clean liquid holding tank re-entry solenoid valve 196 is open,recycling liquid flows back to the clean liquid holding tank 30. Whendischarge solenoid valve 198 is open, recycling liquid flows through adisposable discharge micron filter 202, an accumulation meter 204, adischarge hose 206 mounted on a discharge-hose reel 208, and finallythrough the discharge nozzle into a recycled liquid storage container(not shown). A discharge line "T"-valve 210, adjacent and afterdischarge solenoid valve 198, diverts some of the recycling liquid to asecond additive-loop pressure gauge 212 located on the master controlpanel 16.

As seen in FIG. 6, a plurality of additive compound containers214a,b,c,d,e,f,g store a variety of additive compounds for injectioninto the recycling liquid. Illustrative of such compounds, but not to beunderstood as limiting, are: synthetic rust inhibitors; soluble rustinhibitors; biocides; extreme pressure additives; deodorant agents; bluecolor dyes; and, green color dyes. The additives flow, via conventionaltubing (not shown) to additive metering valves 216,a,b,c,d,e,f,g locatedon the master control panel 16. As seen in FIG. 8, the metering valvesinclude transparent glass tubes 217,a,b,c,d,e,f,g through which theadditives flow, allowing the operator to precisely measure and monitorflow-rates of the additive compounds. The metering valves areadjustable, to regulate the respective flow-rates of the additivecompound.

From the master control panel 16, the additive compounds flow toadditive manifold 32, where they are mixed. The mixed additive compoundsthen flow in a single conventional tube (not shown) to an additivemanifold solenoid valve 218 which is electrically controlled by additiveflow switch 220 located on the master control panel. When the additiveflow switch 220 opens the additive manifold solenoid valve 218, themixed additive compounds flow to a first additive suction "T"-joint 222."T"-joint 222 is structured so that the mixed additive compounds flowand intersect the flow of recycling liquid at a direction that isperpendicular to the flow of the recycling liquid. Consequently, asuction force is applied to the mixed additive compounds by the flow ofthe recycling liquid, thereby drawing the mixed additive compounds intothe recycling liquid. First additive suction "T"-joint 222 is positionedadjacent to and upstream of additive-loop pump 182.

One particular additive compound varies significantly with each type ofrecycling liquid. It is referred to in the art as "neat coolant", andconsists of a concentrated form of the particular metal working coolantbeing recycled. Additionally, certain recycling specifications call forvery precise concentrations of neat coolant. Consequently, neat coolantis stored in a specific neat coolant container 224 and is injected intothe recycling liquid by flowing to, and being pumped by, a separate neatcoolant feed pump 226. The feed pump 226 is a commercially availabletwelve (12) volt pump powered by the van's 38 electrical system, such aspump model number 2100-112, manufactured by Flojet Corp. of 12 MorganStreet, Irvine, Calif. The feed pump is actuated by a conventionalelectric feed pump switch 226 located on the master control panel 16.

Neat coolant leaves the feed pump 226 and flows to a neat coolantmetering valve 230, in the master control panel, which has the samestructure, and flow control features as additive metering valves216a,b,c,d,e,f,g including a transparent glass tube 231 for operatorviewing. From the metering valve 230, the neat coolant flows to a secondadditive suction "T"-joint 232, which has the same structure as thefirst additive suction "T"-joint 222. Second suction "T"-joint is alsopositioned to intersect the flow of recycling liquid upstream ofadditive-loop pump 182, thereby enabling injection of neat coolant intothe recycling liquid.

In operation of the additive-loop 14, the operator 26 actuates theadditive-loop pump 182 through additive-loop pump electric clutch switch188 at the master control panel 16. That causes recycling liquid to flowfrom the clean liquid holding tank 30 through the pump 182; theadditive-loop liquid test valve 192; the clean liquid holding tankre-entry solenoid valve 196; and, back to the clean liquid holding tank30. The operator extracts some of the recycling liquid throughadditive-loop test valve 192 and administers tests to determine theexact amount of additive compounds to inject into the recycling liquid.Additive compound metering valves 216a,b,c,d,e,f,g are then adjusted tometer into the additive manifold 32 specific amounts of additivecompounds required, while additive compound solenoid valve 218 is openallowing the additive compounds to flow into the recycling liquid. Theoperator also tests the recycling liquid to determine the proper amountof neat coolant to meter into the recycling liquid; actuates neatcoolant feed pump 226 through its switch 228; and sets the neat coolantmetering valve 230 to allow injection of the required amount into therecycling liquid.

As the additive compounds and neat coolant are injected, and therecycling liquid circles from, and back to, clean liquid holding tank30, the operator continues testing recycling liquid extracted from theadditive-loop liquid test valve 192 until the recycling liquid satisfiesspecifications. Then the operator opens the discharge solenoid valve 198by its switch 200 at the master control panel 16. Recycling liquid thenflows through a final particle filter, the disposable discharge micronfilter 202; through the accumulation meter 204, to measure the volume ofrecycling liquid discharged; and out of the liquid recycling systemthrough discharge hose 206 and nozzle 34.

When the desired temperature, filtration and separation are achieved bythe filter-loop 12, and the desired specifications achieved by theadditive-loop 14, both loops are kept operating in a straight-run ordischarge-flow sequence, as best shown in FIG. 3. During thedischarge-flow sequence, the operator periodically tests the recyclingliquid, and interrupts the discharge-flow sequence to make necessaryadjustments.

As shown in FIG. 7, a clean water wash cycle portion 234 of the liquidrecycling system allows the operator to clean the liquid recyclingsystem and flush the components that accumulate waste products, afterthe recycling liquid has been completely discharged. Clean water washcycle 234 includes a fresh water holding tank 236 located beneath thevacuum reel 56. Water is pumped from the tank 236 by a commerciallyavailable twelve-volt clean water pump unit 238, such as pump modelnumber 4300-142A, manufactured by Flojet Corp. of 12 Morgan Street,Irvine, Calif.

The pump unit is powered by electrical energy provided by the van's 38engine and controlled by a clean water pump switch 239 on the controlpanel 16. The water then flows, via conventional piping (not shown), tothe solenoid panel 138. At the panel, the water is directed to threesolenoid valves. The first is a waste liquid holding tank entry solenoidvalve 240, which is electrically controlled by a waste tank cleaningswitch 242 on the master control panel 16. The second is a pump primingsolenoid valve 244, controlled by pump priming switch 246, on thecontrol panel 16. The third is a centrifuge wash solenoid valve 248controlled by centrifuge wash switch 250 on the panel 16.

When the clean water pump unit 238 is on and waste liquid holding tankentry solenoid valve 240 is open, water flows into the waste liquidholding tank 18 to flush it clean. When pump priming solenoid valve 244is open, water flows into filter-loop pump 106 to prime it, if needed,to actuate the filter-loop 12. When centrifuge wash solenoid valve 248is open, water flows into the centrifuge 24 to wash accumulated fineparticles out of it, into the centrifuge wash product storage container94 via a centrifuge wash product pipe 158.

A clean water utility hose entry solenoid valve 254, located adjacentand downstream from, clean water pump unit 238, and controlled by cleanwater utility hose switch 256, can open to direct the flow of cleanwater into a utility hose 258 for general cleaning.

When the recycling liquid has been completely discharged, the operatoractuates the clean water pump unit 238, by its switch 239; opens wasteliquid holding tank entry solenoid valve 240, by its switch 242; andengages the filter-loop 12 and additive-loop 14, with additive manifoldsolenoid valve 218 and metering valves 116, 216,a,b,c,d,e,f,g, and 230closed, to completely wash all components of the liquid recycling system10 and purge any remaining recycling liquids out of the system throughdischarge nozzle 34. During this time, centrifuge bypass solenoid valve140 is open, and the centrifuge 24 is on. The operator then openscentrifuge wash solenoid valve 248, permitting water to flushaccumulated fines out of the centrifuge 24 and into the centrifuge washproduct storage container 94.

When the cleaning is completed, the operator actuates the vacuum blower40; closes the vacuum intake solenoid valve 50; opens the waste linesolenoid valve 86; thereby drawing stored centrifuge wash products inthe container 94, and discarded test portions of the recycling liquid intest liquid disposal tray 91, into the waste disposal tank for storageand subsequent discharge through waste disposal valve 104. The operatorhas then recycled the recycling liquid; washed the liquid recyclingsystem 10; and isolated all waste products.

It should be understood by those skilled in the art that obviousstructural modifications can be made without departing from the spiritof the invention. For example, in some instances the heater andtherefore the cooler are not necessary and are deleted, especially wherethe recycling liquid is toxic to bacteria, obviating pasteurization viaheating. Also common sub-elements, such as holding tanks additive valvesand/or manifolds can be deleted or replaced with functional equivalentsknown in the art. Accordingly, reference should be made primarily to theaccompanying claims, rather than to the foregoing specification todetermine the scope of the invention.

Having thus described the invention, what is claimed is:
 1. An apparatusfor recycling contaminated liquids that comprising:a. a filter-loopassembly, positioned to receive recycling liquid, that comprises:i. awaste liquid holding tank that receives and holds recycling liquid; ii.a filter-loop pump, in fluid connection with the waste liquid holdingtank, that selectively moves recycling liquid from the waste liquidholding tank; iii. a flow-rate control valve, in fluid connection withthe filter-loop pump, through which the recycling liquid flows, so thatthe flow-rate of the recycling liquid can be adjusted; iv. a centrifuge,in fluid connection with the filter-loop pump, that adjustably separatesunwanted liquid and particulate contaminates from the recycling liquid;v. a post-centrifuge pump, in fluid connection with the centrifuge, thatmoves recycling liquid from the centrifuge and selectively movesrecycling liquid back to the waste liquid holding tank; vi. afilter-loop test valve, in fluid connection with the post-centrifugepump, that selectively discharges recycling liquid out of thefilter-loop assembly for testing of the recycling liquid, so that, whentests indicate that the recycling liquid is properly filtered, therecycling liquid can be directed from the post-centrifuge pump out ofthe filter-loop assembly; and b. an additive-loop assembly, in fluidconnection with the filter-loop assembly, that comprises:i. a cleanliquid holding tank, in fluid connection with the post-centrifuge pump,that selectively receives and holds recycling liquid from thepost-centrifuge pump; ii. an additive-loop pump, in fluid connectionwith the clean liquid holding tank, that moves recycling liquid from theclean liquid holding tank; iii. an additive suction "T"-joint in fluidconnection with, and positioned between, the clean liquid holding tankand the additive-loop pump; iv. an additive manifold in fluid connectionwith the additive suction "T"-joint; v. a plurality of additive meteringvalves in fluid connection with the additive manifold; vi. a pluralityof additive compound containers, in fluid connection with the additivemetering valves, that contain additive compounds, so that the additivecompounds can be selectively sucked from their containers, at ratescontrolled by the additive metering valves, through the additivemanifold, additive suction "T"-joint, and into the recycling liquid,when the recycling liquid is moving through the suction "T"-joint; vii.an additive-loop test valve, in fluid connection with the additive-looppump, that selectively discharges recycling liquid out of theadditive-loop assembly for testing of the recycling liquid; viii. adischarge valve, in fluid connection with the additive-loop test valve,that selectively directs recycling liquid back to the clean liquidholding tank or out of the additive-loop assembly so that, when testsindicate that the recycling liquid has received proper amounts of theadditives, the recycling liquid may be discharged out of theadditive-loop assembly.
 2. A method of recycling contaminated liquid,which comprises:a. pumping recycling liquid through a filter-loopassembly that includes the steps of:i. adjusting the flow-rate ofrecycling liquid as it is pumped through the filter-loop assembly; ii.passing the flow-rate adjusted recycling liquid through a mechanicalseparator; iii. testing the separated recycling liquid to determine thequality of separation; and b. pumping the recycling liquid from thefilter-loop assembly through an additive-loop assembly, whencontaminates have been substantially separated from the recycling liquidby the filter-loop assembly, that includes the steps of:i. testing theseparated recycling liquid to determine what additive compounds areneeded, and the quantity of any said additive compounds needed, toachieve desired recycling; ii. adjusting additive metering valves toinject quantities of additive compounds into the separated recyclingliquid determined by the testing; iii. directing the separated recyclingliquid to flow by an additive suction "T"-joint; iv. directing additivecompounds through the adjusted additive compound metering valves, andthrough the additive suction "T"-joint into the separated recyclingliquid; v. directing the separated, additive-injected recycling liquidto flow out of the additive-loop assembly.
 3. An apparatus for recyclingcontaminated liquids that comprises:a. a filter-loop assembly,positioned to receive recycling liquid, that comprises:i. a filter-looppump, in fluid connection with the recycling liquid, that selectivelymoves recycling liquid through the filter-loop assembly; ii. amechanical separator, in fluid connection with the filter-loop pump,that adjustably separates unwanted liquid and particulate contaminatesfrom the recycling liquid; iii. a filter-loop test valve, in fluidconnection with the mechanical separator and the filter-loop pump, thatselectively discharges recycling liquid out of the filter-loop assemblyfor testing of the recycling liquid, so that, when tests indicate thatthe recycling liquid is properly filtered, the recycling liquid can bedirected from the mechanical separator out of the filter-loop assembly;and b. an additive-loop assembly, in fluid connection with thefilter-loop assembly, that comprises:i. a clean liquid holding tank, influid connection with the mechanical separator, that selectivelyreceives and holds recycling liquid from the mechanical separator; ii.an additive-loop pump, in fluid connection with the clean liquid holdingtank, that moves recycling liquid from the clean liquid holding tankthrough the additive-loop assembly; iii. at least one additive meteringvalve, in fluid connection with the recycling liquid moving through theadditive-loop assembly; iv. at least one additive compound container, influid connection with the additive metering valve, that contains anadditive compound, so that the additive compound can be selectivelydrawn from the container, at rates controlled by the additive meteringvalve, into the recycling liquid as it moves through the additive-loopassembly; v. an additive-loop test valve, in fluid connection with theadditive-loop pump, that selectively discharges recycling liquid out ofthe additive-loop assembly for testing of the recycling liquid; and vi.a discharge valve, in fluid connection with the additive-loop testvalve, that selectively directs recycling liquid back to the cleanliquid holding tank or out of the additive-loop assembly so that, whentests indicate that the recycling liquid has received proper amounts ofthe additive compound, the recycling liquid may be discharged out of theadditive-loop assembly.
 4. The apparatus of claim 3, wherein thefilter-loop assembly further comprises a flow-rate control valve, influid connection with the filter-loop pump, through which the recyclingliquid flows, so that the flow-rate of the recycling liquid can beadjusted.
 5. The apparatus of claim 3, wherein the filter-loop assemblyfurther comprises a cooler, in fluid connection with the recyclingliquid, that adjustably cools the recycling liquids.
 6. The apparatus ofclaim 3, wherein the mechanical separator comprises a centrifuge influid connection with the filter-loop pump and a post-centrifuge pump,in fluid connection with the centrifuge, that adjustably separateunwanted liquid and particulate contaminates from the recycling liquidand selectively move recycling liquid through the filter-loop assembly.7. The apparatus of claim 3, wherein the additive-loop assembly furthercomprises an additive suction "T"-joint, in fluid connection with, andpositioned between, the clean liquid holding tank and the additive-looppump, so that the additive compound, selectively drawn from the additivecontainer at rates controlled by the additive metering valve, passesthrough the additive suction "T"-joint into the recycling liquid movingthrough the additive-loop assembly.
 8. The apparatus of claim 3, whereinthe additive-loop assembly further comprises an additive manifold, influid connection with, and positioned between, the additive meteringvalve and the recycling liquid moving through the additive-loopassembly, so that the additive compound passes through the additivemanifold into the recycling liquid moving through the additive-loopassembly.
 9. The apparatus of claim 3, wherein the additive-loopassembly further comprises:a. an additive suction "T"-joint, in fluidconnection with, and positioned between, the clean liquid holding tankand the additive-loop pump; and b. an additive manifold, in fluidconnection with, and positioned between, the additive metering valve andthe additive suction "T"-joint, so that the additive compoundselectively drawn from the additive container at rates controlled by theadditive metering valve, passes through the additive manifold andadditive suction "T"-joint into the recycling liquid passing through theadditive-loop assembly.
 10. The apparatus of claim 3, wherein thefilter-loop assembly further comprises a waste liquid holding tank, influid connection with the filter-loop pump, that receives and holdsrecycling liquid.
 11. The apparatus of claim 10, wherein the mechanicalseparator comprises a centrifuge, in fluid connection with the wasteliquid holding tank, and a post-centrifuge pump, in fluid connectionwith the centrifuge, that adjustably separate unwanted liquid andparticulate contaminants from the recycling liquid and selectively moverecycling liquid back to the waste liquid holding tank.
 12. Theapparatus of claim 3, wherein the filter-loop assembly further comprisesa heater, in fluid connection with the filter-loop pump, that adjustablyheats the recycling liquid.
 13. The apparatus of claim 12, wherein thefilter-loop assembly further comprises a cooler, in fluid connectionwith the recycling liquid that adjustably cools the recycling liquid.